Self-aligning screw anchor

ABSTRACT

A SCREW ANCHOR, TO BE ENGAGED BY A BOLT TRAVERSING A WALL, COMPRISES A RIGID BAR ALONGSIDE WHICH A LANYARD IS ENTRAINED THROUGH A HOLE PREFORMED IN THE WALL OR PIERCED IN IT BY AN ENLARGED, POINTED HEAD OF THE BAR, THE LANYARD IS ATTACHED TO THE BAR IN THE VICINITY OF A THREADED TRANSVERSE BORE THEREOF WHICH ALIGNS ITSELF WITH THE PIERCED HOLE WHEN THE BAR IS PULLED FLAT AGAINST THE REMOTE WALL SURFACE AFTER ITS TRAILING END OR FOOT HAS CLEARED THE HOLE, MEANS BEING PROVIDED FOR SWINGING THE BAR OUT OF ALIGNMENT WITH THE LANYARD IN ORDER TO PREVENT ITS FOOT FROM BLOCKING THE PULLBACK.

Sept. 20, 1971 o. 'r. MlLLE'i' 3,605,547

SELF-ALIGNING SCREW ANCHOR Filed April 10, 1969 3 Sheets-Sheet 1 Z; l00--roo 11b kttomey David I. Milief INVENIOR.

Sept. 20, 1971' o. 1'. MILLET SELF-ALIGNING SCREW ANCHOR 3 Sheets-Sheet2 Filed April 10. 1969 7 G. o m H 4 A f z 3 RUIN w/ in R1 4! h, 3 d 3 cW W a 11 n I d David I. Millet INVEN'IOR.

2 FIG. 9 BY pt. 20. 1911" D. T. MM. 3,605,547

SELF-ALIGNING SCREW ANCHOR Filed April 10. 1969 .3 Sheets-Sheet 5 77 F7INVENTORI David I. Mil/9f [77a], BY

(Kurt g RpSS Attorney United States Patent 3,605,547 SELF-ALIGNING SCREWANCHOR David I. Millet, 155 E. 4th St., New York, NY. 10009 Filed Apr.10, 1969, Ser. No. 815,114 Int. Cl. F16b 37/04 US. Cl. 853S 2 ClaimsABSTRACT OF THE DISCLOSURE A screw anchor, to be engaged by a bolttraversing a wall, comprises a rigid bar alongside which a lanyard isentrained through a hole preformed in the wall or pierced in it by anenlarged, pointed head of the bar; the lanyard is attached to the bar inthe vicinity of a threaded transverse bore thereof which aligns itselfwith the pierced hole when the bar is pulled flat against the remotewall surface after its trailing end or foot has cleared the hole, meansbeing provided for swinging the bar out of alignment with the lanyard inorder to prevent its foot fromblocking the pullback.

My present invention relates to a screw anchor engageable by a threadedbolt which traverses a wall member in order to support a load thereon.Such screw anchors are used on panels, container Walls and other usuallybut not necessarily erect wall members of lath and plaster,plasterboard, fiberboard, sheet metal or the like having oneinaccessible, remote side.

Conventional screw anchors of this type are designed as so-called togglenuts, i.e. bars pivotally secured to small nuts engaged by bolts forjoint passage through a hole in a wall member, or as internally threadedtubes with spreadable fingers (known in the trade as mollies) that canbe deployed against the far side of the wall by a tightening of a matingbelt which must then be removed and reinserted by way of a fixture orother load to be secured to the wall. The latter procedure is rathercumbersome and requires advance knowledge of the wall thickness forproper dimensioning of the tube, whereas the use of toggle nuts involvesthe penetration of the load by both the bolt and the bar since the boltcannot be withdrawn in order to prevent irretrievable loss of the nut.

The general object of my present invention is to provide an improvedscrew anchor for the purpose set forth which is of simple design andeasy to manufacture while avoiding the disadvantages set forth above.

More particularly, it is an object of this invention to provide a screwanchor which, unlike the conventional molly, can be used with a widerange of wall thicknesses and, in contradistinction to the known togglenut, can be emplaced in the absence of the load which, subsequently,needs to be traversed only by the bolt so that its boltreceiving hole oreye may be of relatively small diameter.

Another object of my invention is to provide a screw anchor which, inaddition to affording the aforestated advantages, can pierce its ownmounting hole in the panel or other wall member to which it is to beaffixed.

These objects are realized, pursuant to my present invention, by theprovision of a rigid bar having a threaded bore extending transverselyfrom a major face thereof, in combination with an elongate, preferablyflexible element--hereinafter referred to as a lanyard-attached to thatface in the immediate vicinity of the threaded bore and movable withreference to the bar. When designed for or foot clearing the piercedhole, the bar is swung out of alignment with the lanyard by positioningmeans on the bar designed to prevent its foot from blocking a reversemovement whereby, in response to a pull exerted upon the outwardlyprojecting trailing end of the lanyard, the said face of the bar comesto rest against the remote wall surface with its bore in alignment withthe pierced hole. The enlarged head can be omitted along with thepointed edge, if the wall has a preformed hole wide enough to receivethe bar with the lanyard next to it.

The positioning means serving to swing the bar may be constituted by aresilient hinge connecting the bar with the lanyard, in the simplestcase through an extension of the elastic lanyard itself; it is, however,also possible to use one or more springs bearing upon the lanyard whichin that case may be inherently inelastic. Alternatively, or in addition,the bar may have a weighted portion so as to be top-heavy when emergingfrom the pierced hole, thus tilting about a substantially horizontalhinge axis with elevation of the threaded bore above that axis toconfront the hole. A further possibility resides in the provision ofsecond elongate element or lanyard extending alongside thefirst-mentioned one during insertion, the two elements being attached tothe bar on opposite sides of the threaded bore so that by theirmanipulation the bar can be properly oriented.

Besides helping position the bar behind the wall as an anchor nut for ascrew or bolt, the lanyard according to the invention may also serve twofurther functions, namely (a) that of firmly holding the bar onto theremote wall surface during insertion of the bolt and (b) that ofsecuring the bar against rotation with the bolt during the screwing ofthe latter into the threaded bore. The first function involves thefastening of the projecting forward extremity of the lanyard to thefront surface of the wall in a taut state, e.g. with the aid of anadhesive coating or a tack, wherebyparticularly if this element consistsof resilient material-the :bar is held in close contact with the rearwall surface while the bolt, traversing the fixture or other load to besupported thereby, is introduced into the hole alongside or through theflat or tubular lanyard. The second purpose may be accomplished if thelanyard itself lacks the necessary torsibility, by the provision of astiffening strip adjacent the lanyard and/or the presence of a forwardlyprojecting boss on the wall-engaging face of the bar, with the lanyard(reinforced or not) or the boss fitting sufliciently snugly in thepierced hole to resist rotation about the bolt axis. The enlarged headof the bar, when forming a transverse shoulder beyond the point ofattachment of the lanyard, also helps resist rotation since itswedge-shaped profile at that shoulder will tend to bite into theyieldable wall material at a certain distance from the axis of the boreand the bolt. The tendency of the bar to rotate with the bolt can bereduced, however, in a manner known per se by having the threads of thebolt fit only loosely into those of the bar in an initial stage ofinsertion, whereupon the bar may be drawn forward by the bolt toincrease its frictional contact with the wall as the bolt is screwedhome.

The above and other features of my invention Will be described ingreater detail hereinafter with reference to the accompanying drawing inwhich:

FIG. 1 is an isometric view of an embodiment of my invention;

FIGS. 2-5 are side-elevational views of the same embodiment, showingconsecutive steps in the emplacement of my improved screw anchor;

FIGS. 6 and 7 are side views of two modifications of the device of FIGS.l-S;

FIG. 8 is a vertical section of a screw anchor reprepresenting a furtherembodiment;

FIG. 9 is a side view, partly in section, of a modification of thedevice of FIG. 8;

FIG. 10 is a view similar to FIG. 8, illustrating another modification;

FIG. 11 is an end view of the device of FIG. 10, taken in the directionof arrow XI thereof;

FIG. 12 is a side View showing still another screw anchor according tomy invention partly driven through a wall;

FIG. 13 is a similar view showing the embodiment of FIG. 12 fullyemplaced;

FIG. 14 is a front-elevational view of the device of FIG. 13;

FIG. 15 is a view similar to FIG. 10 taken on the line XV-XV of FIG. 13;

FIG. 16 is an isometric view of yet a further embodiment of myinvention;

FIG. 17 is a side view showing the embodiment of FIG. 16 partly driventhrough a wall; and

FIGS. 18 and 19 are views similar to FIG. 7, illustrating two furthermodifications.

In FIGS. 1-5 I have shown a screw anchor 10- according to my invention,comprising a rigid bar 11 (e.g. of metal) which resembles a conventionaltoggle nut in being movably supported on a carrier 12 and provided witha threaded bore 13 designed to receive a bolt 14 (FIG. after beingdriven through a wall 100. Carrier 12,. referred to hereinafter as alanyard, is a resilient strap or thong (e.g. of rubber) which, whenunstressed, is generally L- shaped, with the shorter leg 12:: of the Lcemented or otherwise secured to the bar 11 and the longer leg 12cextending generally perpendicularly therefrom, the two legs beinginterconnected at a bend 12b in the immediate vicinity of bore 13. Bar11 terminates at one end in a pointed head 11aforming a projecting edge11c which overhangs the adjoining leg 12a of the lanyard 12. Bend 12bacts as a resiliently biased hinge which, while urging the leg 120 intoits transverse position, nevertheless allows the same to be flattenedagainst the adjoining face of bar 11 as a coplanar extension of leg 12a.

FIG. 2 illustrates the mounting of the device on a wall by flatteningthe lanyard 12 against the bar 11 and driving the assembly through thewall 100, with the pointed head Ella leading, as indicated by an arrowA. For this purpose, the flat trailing end 111) .of the bar 11 may bestruck by a hammer and then pushed completely through the resulting hole101 in wall 100 with the aid of a screwdriver or other convenient tool.As soon as the end lllb clears the hole 101, lanyard 12 tends to resumeits remembered shape whereupon bar 11 swings into an at least partlyerect position as illustrated in FIG. 3, preferably through an angle of90 or greater. If this angle is obtuse, as shown, a forward pull on thelanyard 12 (arrow B, FIG. 4) brings the head 11a of the bar into contactwith the rear surface of wall 100 whereupon further traction will dragthis head upwardly along that surface, without any risk of jamming,until the position of FIG. 5 is reached in which the bar 11 is drawnflat against the wall 100 with the lanyard held stretched along thebottom of hole 101 to align the bore 13 with that hole for traversal bythe bolt 14. In this position the beveled edge 11c of bar 11, projectingslightly beyond the thickness of lanyard 12, may bite into the rearsurface of Wall 100 to help secure the bar '11 against rotation when thebolt 14 is screwed home. Such rotation of the bar is also resisted bythe lanyard 12 which may be held taut by gluing or otherwise fasteningits free end to the front of wall 100 as illustrated at in FIG. 5.

If the hole 101 is to be plugged for purposes of re plastering, or ifthe screw anchor 10 is to be replaced by another one of different threaddiameter, the lanyard 12 may be detached from the wall whereupon thedevice will simply drop into the space therebeyond.

In FIG. 6 I have shown a modified screw anchor 20 whose bar 21 isgenerally similar to that of the preceding embodiment but whose lanyard22 has a remembered shape of a J or U, consisting of a fixed leg 22a, anintermediate link 22b adjacent the threaded bore 23 and a free leg 22cparallel to leg 22a in the unstressed state. The distance a" betweenlegs 22a and 220 corresponds here to the thickness of the wall on whichthe device is to be mounted; this dispenses with the need for fasteningthe projecting leg of the lanyard to the front surface of the wall.

The screw anchor 30 of FIG. 7 differs from those of the precedingfigures by having a normally arcuate strap 32 secured to its bar 31, bymechanical clamping and/ or cementing, at a recess 31d in the immediatevicinity of the bore 33 thereof. With the lanyard 32 again resting onthe bottom of the pierced hole 101, the bar 31 tends to assume theswung-out position illustrated in FIG. 7 from which it can be pulledfiat against the hole in the manner illustrated in FIG. 5, followed by afastening of the lanyard as described above. Since in this case thebiasing force stored in the lanyard to deflect the bar is distributedover the entire length of the lanyard, the latter can be made of arelatively stiff material such as spring steel.

In FIG. 8 I have shown a screw anchor 40 whose bar 41, generally similarto the bars of the preceding embodiments, is anchored to it by a lanyard42 in the form of a tube of rubber or other resilient material which isadhesively bonded to the bar 41 around its threaded bore 43, the outerdiameter of the tube 42 being slightly less than the maximum width ofthe head 41a of bar 41 in order that the hole 101 pierced by this headmay accommodate a reinforcing strip 45 of less readily deformablematerial, e.g. of soft metal such as copper or brass, extendingalongside the tube while being adhesively bonded thereto. After the bar41 has been positioned fiat against the far side of wall 100 in themanner previously described, tube 42 is partly severed at 42d in theplane of the near face of the wall, so as to form two sections 42a, 42cinterconnected at a bend 42b by the flexible strip 45 which may besupplemented by a residue of intact tube material. Tube section 420 isthen secured to the front surface of the wall while exposing the bore43. The operation is similar to that previously described, except thatthe bolt to be threaded into bore 43 also traverses the tube section42a. Reinforcing strip 45 could also be made of elastic material (eg.spring steel) to supplement the restoring action of tube 42.

In FIG. 9 I have shown a modified screw anchor 40 whose bar 41, designedfor insertion into a preformed hole 101' of a wall 100', is a fiatprismatic body lacking the enlarged head of the preceding embodiments.Tube 42, aligned with bore 43', is similar to tube 42 of FIG. 8.

The screw anchor 50 illustrated in FIGS. 10 and 11 has its bar 51 formedwith a rearwardly divergent gap 51d closely spaced from the bore 53,this gap receiving an end of a resilient tube 52 which is cut away at52d so as to form a hinge 52b immediately adjacent the wallcontactingface of the bar. The end of tube 52 may be molded directly into the gap51d of bar 51. The forwardly projecting extremity of the tubular lanyard52 is split into two halves 52a, 520 which, when the assembly isproperly positioned, are held against the front surface of wall 100 byan annular washer 56 with an adhesive coating engaging the wall. Thecenter hole 56a of this washer gives access to the bore 53 of bar 51,the engaging bolt again passing through a section of the tubularlanyard.

The tubes 42 and S2 of FIGS. 8-1l could also be made of a syntheticelastomer such as polyethylene or polypropylene, and in the most commoncase may have diameters and wall thicknesses similar to those of anartificial drinking straw.

In FIGS. 12-1S I have shown a screw anchor 60 having means forpositively preventing any rotation of its bar 61 with reference to thesupporting wall 100. The

head 61a of this bar is wedge-shaped and adjoins, without overhang, thebody of the bar which converges toward the opposite end 61b; a boss 61e,rising from the initially upwardly positioned face of the bar, traversesthe bore 63 and is set sufiiciently far back from the head 61a to clearthe hole 101 pierced by this head in the wall 100 as seen in FIG. 12. Alanyard 62, here shown to be of the strap type similar to thatillustrated in FIGS. 1-5, is secured to the bar in the aforedescribedmanner at a recess 61d adjacent boss 612. The noncircular profile ofboss 61e, here shown to be rectangular, is slightly smaller than that ofthe head 61a at its widest point so that this boss, together withlanyard 62, fits closely in the hole 101 as best seen in FIG. 15,thereby holding the bar 61 against rotary entrainment by the matingbolt. To facilitate the insertion of boss 61e into the hole 101 upon aforward pull on the lanyard 12, the lateral faces of the bar 61 may alsobe given a slight draft as seen in FIG. 14; the width of lanyard 62 maythen somewhat exceed that of bass 612, corresponding to the maximumwidth of head 61a.

In this embodiment the lanyard 62 follows the bar 61 through the wall inthe wake not only of its head 61a but also of boss 61e, coming to reston the bottom of hole 101 only after the bar 61 has been pushed fullythrough the wall. The lanyard, in this case, must be stiffer than in thepreceding embodiments to overcome the top-heavy weight distribution ofbar 61a.

In FIGS. 16 and 17 I have shown a screw anchor 70 whose bar 71 isattached to two lanyards 72, 72" on opposite sides of its bore 73.Lanyard 72 is secured to the bar 71 adjacent the transverse edge 17c ofhead 71a whereas lanyard 72" engages the bar just beyond a step 61 of aheight substantially corresponding to the thickness of that lanyard,whereby the two thongs come to lie one atop the other on the bar 71 inthe shelter of is head 71:: when the bar is driven through a wall 100 asshown in FIG. 17. Bar 71 has a pair of laterally spaced lugs 71g whichbracket the reduced extremities 72a 72a" of the lanyards when the sameare folded against the bar in the insertion position of FIG. 17, thesereduced extremities being subsequently bent in opposite directions (asillustrated in FIG. 16) to immobilize the bar on the wall, as previouslydescribed, while giving access to the bore 73. For this purpose a washer56 (FIGS. and 11) may be used to hold the ends 72a and 72a" against thefront surface of the wall 100.

With the embodiment of FIGS. 16 and 17 it is not essential that thelanyards be made of elastic material since the erection of the bar afterthe traverse of the wall can be controlled by relative manipulation ofthe two extremities 72a and 72a".

FIG. 18 shows a screw anchor 80 whose bar 81, similar to that of FIGS.1-5, is hingedly attached at 81d to a lanyard 82 which in this instancemay be a rigid rod or strip. A spring 87 tends to swing the element 82into a position substantially transverse to bar 81 whereby, uponpenetration of the wall 100, the head 81a of the bar pivots upwardly(arrow C) so that the foot of the bar recedes from wall 100 into anonblocking position. Spring 87 is, of course, representative of anysuitable biasing means tending to bring about such clockwise motion ofbar 81 with reference to lanyard 82.

In FIG. 19 I have shown a further embodiment in the form of a screwanchor 90 whose bar 91 has a top-heavy head 91a, the lanyard 92 beinghingedly secured to the bar at a location 91d between the head and thebore 93. In this case, too, the lanyard 92 may be a rod or strip ofsubstantially conresilient material. As the bar 91 clears the hole 101,it tilts counterclockwise (arrow 1)) about the hinge 91d under its ownweight so that its tail end 91b again assumes a nonblocking attitude.

It will be understood that compatible features of different embodiments(e.g. the boss 61e of FIGS. 12-15 and the spring 87 of FIG. 18) may becombined and that the precise shapes and specific materials hereindisclosed are not crtical.

I claim:

1. A screw anchor comprising a rigid bar having a major face providedwith a threaded transverse bore located between the ends of the bar, oneof said ends being an enlarged head with a pointed forward edge and witha rear edge parallel to said face at a location of maximum thickness ofsaid bar ahead of said bore, and a resilient tube secured to said bar atsaid face at a location of reduced thickness in the immediate vicinityof said bore and adapted to lie alongside said face in the shelter ofsaid transverse rear edge upon passage of said bar through a hole in awall pierced by said head, said tube forming with said bar a junction sobiased as to swing said bar out of alignment with said tube upon thetrailing end of said bar clearing said hole whereby said face comes tolie against a rear surface of said wall, with said bore confronting saidhole, upon a pull on a projecting extremity of said tube trailing saidbar, said tube having an inner diameter greater than that of said boreand being provided with a cut-away portion adjacent said face for givingclearance to a bolt traversing said hole within said tube and engagingthe threads of said bore.

2. A screw anchor as defined in claim 1 wherein the front extremity ofsaid tube is longitudinally split into two halves attachable to thefront surface of said wall on opposite sides of said hole.

References Cited V UNITED STATES PATENTS 991,426 5/1911 Clements -3K2,398,220 4/ 1946 Gelpscke 853K 2,919,089 12/1959 Durham 85-3 3,211,04210/1965 Fischer 853 EDWARD C. ALLEN, Primary Examiner

